1. Field of the Invention
This invention relates to the making of wire and similar elongate members and more particularly to the making of such wire utilizing a filled billet extrusion technique.
2. Prior Art Statement
It is known in the art to provide a method of making wire and similar elongate members of so-called high performance alloys wherein the method comprises the steps of providing a cylindrical can which has a closed end, an open end, and a central longitudinal axis; disposing a plurality of rods into the can through its open end in parallel relation with each other and parallel to the longitudinal axis; introducing a powdered filler material into the can to fill the spaces between the rods and the interior surface of the can; attaching a cap to the open end of the can to thus complete a filled billet; heating the filled billet to a temperature approximately equal to the forging temperature of the rods; extruding the filled billet through an extrusion die to effect an area reduction in the cross section thereof and of the rods therewithin; cooling the extruded filled billet; and removing the extruded can from around the extruded rods, and as disclosed in U.S. Pat. No. 4,209,122.
It is also known to manufacture elongate members of high performance alloys by the filled billet extrusion technique using stacked lamina disposed in a metal can and with each lamina having aligned perforations therein so that once the lamina are disposed in stacked relation associated perforations in the can are aligned to receive an elongate preform which is to be extruded and as disclosed in U.S. Pat. No. 3,788,820.
It is also known to form fine wire filaments by disposing a bundle of wires within a can, disposing metal powder between the wires and can or chordal sector pieces between the wires and can as disclosed in U.S. Pat. Nos. 3,394,213 and 3,505,039.
However in the above-mentioned prior art patents the application of heat and pressure, during extrusion, serves to bond the separate billet parts together; and, it is very difficult to mechanically remove the filler means (whether originally in the form of powder, plates, tubes, chordal sector pieces, or other form) from around the parts being processed. Acid is often required to remove such filler means by dissolution.
The high performance alloys referred to above are disclosed in U.S. Pat. No. 4,209,122 and thus will not be repeated because the entire teachings of such patent are incorporated herein by reference thereto. In addition, when the separable filler means is in the form of a powder, the basic desirable characteristics for such a powder disclosed in U.S. Pat. No. 4,209,122 are applicable to this invention and are also incorporated herein by reference thereto.
It is also known to provide a process for reducing metal rods, wires, strips and the like be drawing, rolling, and analogous operations (all of which utilize small compressive forces when compared to extrusion operations) by placing the rods, wires, strips and the like in a casing surrounded by a packing material to define a billet and then proceeding with reducing operations on such billet and as disclosed in U.S. Pat. No. 2,050,298. Because of the above-mentioned small compressive forces drawing, rolling, and analogous operations are not suitable for making elongate rods of high performance alloys from castings.
However, the known apparatus and methods, including the ones disclosed in the above-mentioned patents have certain deficiencies which preclude the forming of wires and like elongate members of high quality and in an economical manner.